Firetube boiler



y 0, 1955 R. R. ADAMS 2,707,942

FIRETUBE BOILER Filed Sept. 14, 1951 3 Sheets-Sheet 1 ATTORNEY.

y 0, 1955 R. R. ADAMS 2,707,942

FIRETUBE BOILER Filed Sept. 14 1951 Shets-Sheet 2 INVENTOR. ROBERT R. ADAM5.

ddm [Q ATTORNEY.

y 1955 R. R. ADAMS 2,707,942

FIRETUBE BOILER Filed Sept. 14, 1951 3 Sheets-Sheet 3 INVENTOR. ROBERTR. ADAMS.

ATTORNEY.

United States PatentO F IRETUBE BOILER Robert R. Adams, Williamsport,Pa., assignor to Avco Manufacturing Corporation, Cincinnati, Ohio, acorporation of Delaware Application September 14, 1951, Serial No.246,653

9 Claims. (Cl. 122-52) The present invention relates to a stationaryboiler installation for use in producing steam or hot water for smallsized industrial establishments.

More particularly, the present invention relates to a firetube boilerwhich can be easily erected in the basement of an existing building andwhich is characterized by an unusually low water level while also beinghighly efiicient and capable of producing substantially dry steam atoutputs in excess of rated capacity.

Firetube boilers have been in use for a great many years, and ofteninclude a cylindrical shell in which the firetube passes are arrangedone above the other so that the products of combustion from the fireboxascend successively through the banks of the tubes. Practically all ofthese currently used firetube boilers are characterized by a relativelyhigh water level as well as by difiicult installation problems. While itis true that this latter difiiculty has been overcome in part by makingboilers in sections which can be subsequently welded together aterection, this solution of the installation problem is expensive, is notlooked upon with favor, and, in fact, is actually prohibited in certainStates.

In contrast, boilers made according to the present invention can beeasily installed in a very limited space without welding of any sort.Furthermore, the compo nents of the boiler pass easily through existingbuilding openings. In addition, these boilers, because of their lowwater line height, facilitate drainage of condensate and can readilyaccommodate existing piping in most buildings.

Briefly stated, the boiler installation of the present inventioncomprises a pair of juxtaposed, horizontally arranged, cylindricalshells to which are attached in depending relationship front, rear, andside water legs which define a fire box beneath the contiguous portionsof the boiler shells. Each of the side water legs subtends the lowermostportion of its associated boiler shell so that sludge and otheraccumulations from the boiler automatically settle within the waterlegs, thus making the boiler shells practically self-cleaning.

The boiler shells are recessed at their rear ends and with the rearwater legs define an uptake from the fire box through which the hotgases pass to a group of firetubes in each of the adjacent boilershells. Each boiler shell contains two horizontally spaced groups offiretubes, the inner group in each shell extending between the uptakeand a smoke box at the forward end of the boiler installation. Eachouter group of tubes extends between a smoke box at the front end of theboiler and a smoke box and breeching at the rear of the boiler shells.it is to be noted that the groups of boiler tubes constitute gas passesin laterally spaced relationship rather than in conventional verticallyspaced disposition. Through this arrangement of boiler tubes and theoverall boiler design, the water level within the boiler shells can bekept very low for an installation of relatively high rating.

According to the present invention, a front and a rear water leg areformed integrally with each of the boiler shells. Thus, the entireboiler installation is split in half, each half including a cylindricalshell side water leg, and a front and rear water leg. These halves canbe easily passed through the average building opening and erected withinthe basement of most existing structures. Even if a new structure-beinvolved, the possibility of so erecting the boiler is of greatimportance, since the cost is considerable for each additional foot offoundation and excavation. 1

In view of the foregoing, it is an object of the present invention toprovide a firetube boiler installation which has a very low normaloperating water line height.

A further object of the present invention is to provide a boilerinstallation in which the portions of the boiler shells facing the firebox, or in other words the crown sheets, are self-cleaning, sludge andother accumulations tending to settle in water legs secured to theboiler shells.

It is also an object of the present invention to provide a boilerinstallation including a horizontally disposed cylindrical shell towhich a vertically disposed water leg is secured, the water legsubtending the lowermost portion of the shell.

An important object of the present invention is the provision of aboiler having the greatest fire box height at the center of theinstallation.

Another very important objective is the provision in a boilerinstallation of a large steam liberating area at the water line wherebysubstantially dry steam is produced despite the fact that the boiler isoperated considerably in excess of its rated capacity.

A still further object of the present invention is to provide a boilerinstallation comprising a pair of horizontally arranged, parallelcylindrical shells each shell incorporating horizontally spaced groupsof firetubes through which the gases pass in succession from an up: takewhich is centrally located at the rear of the fire box and is incommunication with one group of fire tubes within each boiler shell.

Still another object of the present invention is to pro vide a boilermade in sections which can be readily moved through an average sizedbuilding opening and subsequently erected without welding.

The novel features that are considered characteristic of the presentinvention are set forth in the appended claims; the invention itself,however, both as to its organization and use, together with additionalobjects and advantages thereof will best be understood from thefollowing description of a preferred embodiment when read in conjunctionwith the accompanying drawings, in which:

Figure l is a front elevational view of the complete boilerinstallation, one-half of the boiler being shown in cross section toillustrate the interior construction thereof;

Figure 2 is a vertical longitudinal sectional view of the. boilerinstallation taken on plane 2-2 of Figure 1; and

Figure 3 is a horizontal longitudinal-sectional view taken on plane 3--3of Figure 1 showing the horizontally spaced disposition of the groups ofboiler tubes Within one of the boiler shells. 1

As illustrated particularly well in Figure 1, the present inventioncomprises a pair of parallel, juxtaposed, horizontally arrangedcylindrical boiler shells 1 and 2, each of which has an integrallysecured side water leg I 3 and 4, respectively. The boiler shells 1 and2 are also connected to front water legs 5 and 5a and rear water legs 6and 6a, respectively. These water legs define a fire box, generallydesignated 7, theupper extremities of which are defined by thecontiguous crownsheets 8 and 9 of boiler shells 1 and 2, respectively.

With reference to Figure 2, the boiler installation can be erected on asetting, generally designated 10, which may include a structural steelframework 11 lined with refractory brick 12. A transverse bridgewall 13may be provided across the fire box as is conventional in firetubeboilers to deflect the hot gases and products of combustion upwardlyagainst the crown sheets 'of the boiler shells.

Boilers of the type to which the present invention relates may be tiredby any conventional method for burning coal, oil, or gas. For purposesof illustration, a burner nozzle 13a has been illustrated at the frontof the boiler installation for injecting oil into the fire box thecombustion of which produces 'hot gases which pass underneath the boilershells and through a plurality of firetubes 14 in order to heat water 15within the boiler shells and water legs.

The firetubes within both boiler shells are divided into horizontallyspaced groups. With reference to boiler shell 1, it will be noted thattwo groups of boiler tubes 16 and 17 are provided whereas in boilershell 2 groups 18 and 19 are provided. The adjacent groups of firetubes17 and 18 are relatively short compared to groups 16 and 19, as

best illustrated in Figure 3, which shows the ends 20 of the shortfiretubes 1S projecting rearwardly into an uptake 21 defined by the rearends of the boiler shells and the rear water legs 6 and 6a.

The uptake is substantially as wide as fire box 7. In this way, there isfree passage for the hot gases, formed within the fire box, which firstflow upwardly and rearwardly past substantially the entire area of thecrown sheets 8 and 9, and then into the uptake 21 from which the gasesflow forwardly through the groups of firetubes 5 17 and 18.

With reference to Figure 3, it will be noted that the gases pass fromthe firetube groups 17 and 18 to smoke boxes 22 and 23, respectively, Inthese smoke boxes the gases reverse their direction of flow and enterthe other groups of tubes of the associated boiler shells. For instance,with respect to boiler shell 1 the gases enter smoke box 22 fromfiretubes 17, reverse their direction and flow rearwardly throughfiretubes 16. Similarly, gases enter smoke box 23 from the group offiretubes 18, reverse their direction of flow and enter firetubes 19.The gases pass from the firetubes 16 and 19 into a common rear smoke box24 where the gases merge and pass through a breeching 25 to a commonsmoke stack (not shown).

As will be readily appreciated by those skilled in the art, the passageof hot gases underneath the boiler shells and through the firetubesimparts a large amount of heat to the water. Heat is also transferreddirectly from the fire box into the water legs, thereby reducing thetemperature of the furnace volume to a practical level and increasingthe capacity of the boiler installation. As the water increases intemperature, steam is generated which collects in steam spaces 26 and 27which are interconnected by a common manifold 28 used to convey thesteam to a piping system (not shown) for use in heating .q.

buildings or for other desirable purposes.

There is free water circulation throughout each boiler shell and itsassociated water legs which are secured. as by welding, to the shell. Inparticular, it is to be noted in Figure 1 that holes 29 are provided inthe lower portion of each boiler shell subtended by the side water legs.A common pipe line 30 introduces water to both sides of the boilerinstallation with the result that there is complete equalization of thewater level within the two sections.

Although the present invention has been described primarily withreference to a steam generating installation, it should be appreciatedthat it may also be used to produce hot water for a'hot water heatingsystem with equal facility.

As will 'be understood by those skilled in the art, the hottest portionsof the fire box are the crown sheets 8 and 9. There is a tendency forsludge and other accumulations of foreign matter to settle on the crownsheets of many conventional firetube boilers. In the present incenterwhere the crown sheets are contiguous.

vention, however, the inclination of the crown sheets 8 and 9 incombination with their being adjacent and in full communication with thewater legs 3 and 4, respectively, induces a movement of the sludgethrough openings 29 into the water legs 3 and 4 where it settles to thebottom and can easily be flushed out periodically through clean outholes 31 at the sides of the water legs.

This self-cleaning feature of the subject invention is very important,since it assures that at all times the interior surfaces of the crownsheets will be free and clear of sludge and other deleterious depositswhich would otherwise act as an insulating layer and impede heattransfer through the boiler shells.

it is also noteworthy that the fire box is highest at the This is highlybeneficial and favors complete combustion of the fuel within the firebox and also tends to minimize soot deposits on any of the heat transfersurfaces of the boiler installation.

By arranging the groups of firetubes in spaced horizontal relationship,the gas passes are maintained at a minimum elevation. In this way, thewater level, indicated at 32, is kept at an absolute minimum whichfavors the use of the present boiler in relatively shallow basements andmakes use of the boiler desirable in new structures since a minimumexcavation is required to accommodate the installation. Furthermore, theboiler favors drainage from existing pipe lines within buildings inwhich it is installed, since its water level is so low as to be beneaththat of most condensate return lines ordinarily encountered.

Another important feature of the present invention is the constructionof the boiler installation in sections. The boiler is split vertically,each section including a boiler shell, a side water leg, and a front andrear water leg. This is of considerable importance since the sections ofthe boiler can be readily passed through existing building openings eventhough somewhat under-sized, and the boiler can be erected easily in arelatively confined space. It is important to note that no welding isnecessary for installing the two sections.

Another advantage of the present invention is the fact that noreinforcing stays are necessary in the boiler shells because of theircylindrical formation and relatively small diameter. Stays 33 areprovided in the water legs for reinforcement purposes. These stays areeasily provided because of the flat sides of the water legs, and therelatively small thickness involved. Thus, the boiler disclosed can bereadily fabricated with ordinary boiler making equipment, and noexpensive and intricate staying problems are encountered.

Another feature of importance in the present invention is the largesteam liberating area inherently present at the water line 32. By virtueof this large area, steam can be generated within the boiler shells witha minimum of moisture entrapment with the result that steam ofninety-eight per cent quality can be produced at an operating load ofover two hundred per cent rated capacity.

ln view of the foregoing description, it will be appreciated by thosewell versed in the art that the present inventon provides a boilerinstallation which is not only highly desirable from the viewpoint offabrication and erection, but which also favors the economical and rapidproduction of substantially dry steam. It will also be appre ciated thatthe boiler installation is highly desirable from the viewpoint of havinga high fire box defined by selfcleaning crown sheets and surroundingwater legs which can be readily reinforced by short stays. The integralconstruction of the water legs with the boiler shells and the absence ofany welding at the time of erection favors greatly the production of aleak-free installation.

raving described a preferred embodiment of my invention, I claim:

I. A sectional boiler installation comprising adjacent halves eachcomprising a horizontal, cylindrical boiler shell and front, rear andside water legs secured to said shell, the halves of the boilerinstallation being located with the boiler shells in contiguousdisposition with the Water legs defining a fire box beneath said boilershells, the highest region of the fire box being defined by thecontiguous surfaces of said shells; a plurality of firetubes passingthrough each of said shells, the firetubes within each shell comprisingtwo horizontally spaced groups; said boiler shells and rear water legsdefining an uptake for directing hot gases from the fire box into theinner group of fire tubes in each boiler shell; and means at the end ofthe boiler shells remote from the uptake for directing the gases fromeach inner group of firetubes to the outer group of firetubes in theassociated shell.

2. Apparatus as defined in claim 1 in which said inner group offiretubes is shorter than said outer group of firetubes, the inner groupterminating in the uptake in communication with the fire box.

3. In combination, a sectional boiler installation comprising verticallysplit halves each of which includes a :1:

horizontal, cylindrical boiler shell and front, rear, and side waterlegs, the water legs and shells defining a fire box, the side water legssubtending the lowermost portions of the associated boiler shells, theboiler shells defining openings in their lower walls permitting freecirculation between said side water legs and boiler shells respectively,a plurality of firetubes passing longitudinally through each of saidshells, the firetubes within each shell comprising two horizontallyspaced groups, said boiler shells and rear water legs defining an uptakefor directing hot gases from the fire box to the inner groups offiretubes in each boiler shell and means remote from the uptakeinterconnecting the groups of associated firetubes in each boiler shell.

4. In combination, a sectional boiler installation comprising verticallysplit halves each of which includes a horizontal, cylindrical boilershell and front, rear, and side water legs, said water legs and shellsdefining a fire box; said side water legs subtending the lowermostportions of the associated boiler shells, each boiler shell being infree communication with its side water leg; a plurality of firetubespassing longitudinally through each of said shells, said firetubeswithin each shell comprising two horizontally spaced groups; said boilershells and rear water legs defining an uptake for directing hot gasesfrom the fire box to the inner groups of firetubes in each boiler shell;and means remote from the uptake interconnecting the groups ofassociated firetubes in each boiler shell.

5. in combination, a sectional boiler installation comprising splithalves each of which includes a horizontal, cylindrical boiler shell andfront, rear and side water legs, said water legs and shells defining afire box; said side water legs subtending the lowermost portions of theassociated boiler shells and being in free communication therewith; aplurality of firetubes extending longitudinally through said shells,said firetubes of each shell being arranged in two horizontally spacedgroups; the inner adjacent groups of firetubes in said boiler shellsbeing shorter than the other groups of firetubes and being incommunication with an uptake defined in part by said boiler shells andwater legs, the uptake being in communication with the firebox; andmeans at the ends of said boiler shells remote from the uptakeinterconnecting said groups of firetubes of each boiler shell.

6. In combination, a sectional boiler installation comprising verticallysplit halves each of which includes a horizontal, cylindrical boilershell and a side water leg, said Water legs and shells defining a firebox; said side Water legs subtending the lowermost portions of theassociated boiler shells and being in free communication therewithaplurality of fire tubes passing longitudinally through each of saidshells, said firetubes within each shell comprising two horizontallyarranged groups; an uptake defined in part by said shells for directinghot gases from the fire box to the inner group of firetubes in eachboiler shell; and means remote from said uptake interconnecting thegroups of associated firetubes in each boiler shell.

7. In combination, a boiler installation comprising a pair ofhorizontal, cylindrical, contiguous boiler shells; side and rear waterlegs connected to each shell; said shells and water legs defining a firebox; said side water legs subtending the lowermost portions of theassociated boiler shells and being in free communication therewith; aplurality of firetubes extending longitudinally through said shells,said firetubes of each shell comprising two horizontally arrangedgroups; the inner adjacent groups of fire tubes in said boiler shellsbeing shorter than the other groups of fire tubes; said rear water legsand shells at the ends of said shorter firetubes defining a centraluptake communicating with the fire box and delivering hot gases to theinner group of firetubes in each boiler shell; and means remote from theuptake interconnecting the groups of firetubes in each shell.

8. A sectional boiler installation comprising adjacent halves eachcomprising a horizontal, cylindrical boiler shell and water legs securedto said shell, the halves of the boiler installation being located withsaid boiler shells in contiguous disposition with the water legsdefining a fire box beneath said boiler shells, the highest region ofthe fire box being defined by the contiguous surfaces of said shells; aplurality of firetubes passing through each of said shells, thefiretubes within each shell comprising two horizontally spaced groups;said boiler shells and water legs defining a central uptake fordirecting hot gases from the fire box into the inner group of firetubesin each boiler shell; and means at the end of the boiler shells remotefrom the uptake for directing the hot gases from each inner group offiretubes to the outer group of firetubes in the associated shell.

9. Apparatus as defined in claim 8 in which said inner group offiretubes is shorter than said outer group of firetubes, the inner groupterminating in the uptake in communication with the fire box.

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